AssetUNS#

OpenFactory AssetUNS class.

class openfactory.assets.asset_uns_class.AssetUNS(uns_id, ksqlClient, bootstrap_servers, asset_router_url=None)[source]#

Bases: BaseAsset

Represents an OpenFactory Asset using the UNS identifier.

This class encapsulates Asset metadata and a Kafka producer responsible for sending Asset data. It uses the ksqlDB topology based on the ASSETS_STREAM_UNS stream to handle Asset data.

Note

All write operations to the asset take place in the assets stream.

KSQL_ASSET_TABLE#

Name of ksqlDB table of Asset states (assets_uns)

Type:

str

KSQL_ASSET_ID#

ksqlDB ID used to identify the Asset (uns_id) in the KSQL_ASSET_TABLE

Type:

str

ASSET_ID#

value of the identifer of the Asset (uns_id) used in the KSQL_ASSET_TABLE

Type:

str

ksql#

Client for interacting with ksqlDB.

Type:

KSQLDBClient

bootstrap_servers#

Kafka bootstrap server address.

Type:

str

asset_router_url#

Asset Router URL from the OpenFactory Fan-Out-Layer.

Type:

str

ASSET_CONSUMER_CLASS#

Kafka consumer class for reading messages from Asset strean.

Type:

KafkaAssetUNSConsumer

producer#

Kafka producer instance for sending Asset messages.

Type:

AssetProducer

Example usage:

import time
from openfactory.assets import AssetUNS
from openfactory.kafka import KSQLDBClient

ksql = KSQLDBClient('http://localhost:8088')
cnc = AssetUNS('cnc-003', ksqlClient=ksql, bootstrap_servers='localhost:9092')

# list samples
print(cnc.samples())
print(cnc.Zact.value)
print(cnc.Zact.type)
print(cnc.Zact.timestamp)

# redefine an attribute value
cnc.Zact = 10.0
print(cnc.Zact.value)

# callbacks for subscriptions
def on_messages(msg_key, msg_value):
    print(f"[Message] [{msg_key}] {msg_value}")

def on_sample(msg_key, msg_value):
    print(f"[Sample] [{msg_key}] {msg_value}")

def on_event(msg_key, msg_value):
    print(f"[Event] [{msg_key}] {msg_value}")

def on_condition(msg_key, msg_value):
    print(f"[Condition] [{msg_key}] {msg_value}")

cnc.subscribe_to_messages(on_messages, 'demo_messages_group')
cnc.subscribe_to_samples(on_sample, 'demo_samples_group')
cnc.subscribe_to_events(on_event, 'demo_events_group')
cnc.subscribe_to_conditions(on_condition, 'demo_conditions_group')

# run a main loop while subscriptions remain active
try:
    while True:
        time.sleep(1)
except KeyboardInterrupt:
    print("Stopping consumer threads ...")
    cnc.stop_messages_subscription()
    cnc.stop_samples_subscription()
    cnc.stop_events_subscription()
    cnc.stop_conditions_subscription()
    print("Consumers stopped")
finally:
    ksql.close()
__init__(uns_id, ksqlClient, bootstrap_servers, asset_router_url=None)[source]#

Initializes the Asset with metadata and a Kafka producer.

Parameters:

  • uns_id (str) – UNS identifier of the asset.

  • ksqlClient (KSQLDBClient) – Client for interacting with ksqlDB.

  • bootstrap_servers (str) – Kafka bootstrap server address.

  • asset_router_url (str | None) – Asset Router URL from the OpenFactory Fan-Out-Layer.

Raises:

OFAException – If asset_router_url is not provided and the ASSET_ROUTER_URL environment variable is not set.

Note

  • If asset_router_url is not explicitly provided, the constructor will attempt to read it from the ASSET_ROUTER_URL environment variable.

  • When used in an OpenFactoryApp deployed on the OpenFactory cluster, the environment variable ASSET_ROUTER_URL will be set.

add_attribute(asset_attribute)#

Adds a new attribute to the asset.

Return type:

None

Parameters:

asset_attribute (AssetAttribute) – The attribute to be added.

add_reference_above(above_asset_reference)#

Adds a reference to an asset above the current asset.

Return type:

None

Parameters:

above_asset_reference (str) – The asset-reference of the asset above the current one to be added.

add_reference_below(below_asset_reference)#

Adds a reference to an asset below the current asset.

Return type:

None

Parameters:

below_asset_reference (str) – The asset-reference of the asset below the current one to be added.

property asset_uuid: str#

Returns the asset UUID based on runtime state.

Returns:

str – The asset’s UUID.

attributes()#

Returns all non-Method attribute IDs associated with this asset.

Return type:

List[str]

Returns:

List[str] – A list of attribute IDs.

close()#

Gracefully closes the Asset and frees ressources.

Steps performed:

  1. Stops all NATS subscribers (unsubscribe + close NATS connection).

  2. Cancels any remaining tasks in the AsyncLoopThread.

  3. Stops the AsyncLoopThread and joins the thread.

Warning

After calling this method, the Asset instance should not be used again.

conditions()#

Returns all condition-type attributes for this asset.

Return type:

List[Dict[str, Any]]

Returns:

List[Dict] –

A list of dictionaries, each containing:

  • ID (str): The attribute ID.

  • VALUE (Any): The value of the condition.

  • TAG (str): The condition tag (‘Normal’, ‘Warning’, ‘Fault’)

events()#

Returns all event-type attributes for this asset.

Return type:

List[Dict[str, Any]]

Returns:

List[Dict] –

A list of dictionaries, each containing:

  • ID (str): The attribute ID.

  • VALUE (Any): The value of the event.

  • TAG (str): The cleaned tag name with placeholders removed.

method(method, sender_uuid, args=None)#

Requests the execution of a method for the asset.

This function further sets the corresponding callable attribute with the name of the method (e.g. GenerateCode) to trigger the command execution.

Methods execution can be requested in two ways:

  1. Using the method() interface:

    asset.method('GenerateCode', sender_uuid='SENDER-ID', args=[('Code', '123')])

  2. Or directly via the generated callable attribute:

    asset.GenerateCode(sender_uuid='SENDER-ID', Code='123')

In both cases, sender_uuid must be provided in addition to the command’s named arguments.

Note

Named arguments are case sensitive and can be discovered by calling methods().

Parameters:

  • method (str) – Name of the method to be executed.

  • sender_uuid (str) – Asset UUID of the asset sending the request.

  • args (Optional[List[Tuple[str, str]]]) – List of (argument_name, value) pairs. All values must be strings. Defaults to empty list if not provided.

Returns:

str – The correlation_id of the command, which can be used to track the response.

Return type:

str

methods()#

Returns method-type attributes for this asset.

Return type:

Dict[str, dict | None]

Returns:

Dict[str, dict | None] – Dictionary mapping method IDs to their parsed method contract (description + arguments). Returns None if no value is stored.

Returned Dictionnary Example

{
   "GenerateCode": {
       "description": "GenerateCode",
       "arguments": [
         {
           "name": "Code",
           "description": "Barcode to generate (empty for random)"
         }
       ]
   },
   "SetAutomaticMode": {
       "description": "SetAutomaticMode",
       "arguments": []
   },
   "SetManualMode": {
       "description": "SetManualMode",
       "arguments": []
   }
}
references_above()#

Retrieves a list of assets above the current asset.

Return type:

List[Self]

Returns:

List[Self] – A list of asset objects that are above the current asset.

references_above_uuid()#

Retrieves a list of asset-references of assets above the current asset.

Return type:

List[str]

Returns:

List[str] – A list of asset-references (as strings) that are above the current asset.

references_below()#

Retrieves a list of assets below the current asset.

Return type:

List[Self]

Returns:

List[Self] – A list of asset objects that are below the current asset.

references_below_uuid()#

Retrieves a list of asset-references below the current asset.

Return type:

List[str]

Returns:

List[str] – A list of asset-references (as strings) that are below the current asset.

samples()#

Returns all sample-type attributes for this asset.

Return type:

List[Dict[str, Any]]

Returns:

List[Dict] –

A list of dictionaries, each containing:

  • ID (str): The attribute ID.

  • VALUE (Any): The value of the sample.

  • TAG (str): The cleaned tag name with placeholders removed.

stop_attribute_subscription(attribute_id)#

Stops the NATS consumer and gracefully shuts down the subscription.

Return type:

None

Parameters:

attribute_id (str) – The attribute ID to for which to stop the subscription.

stop_conditions_subscription()#

Stops the NATS consumer and gracefully shuts down the subscription for conditions.

Return type:

None

stop_events_subscription()#

Stops the NATS consumer and gracefully shuts down the subscription for events.

Return type:

None

stop_messages_subscription()#

Stops the NATS consumer and gracefully shuts down the subscription.

Return type:

None

stop_samples_subscription()#

Stops the NATS consumer and gracefully shuts down the subscription for samples.

Return type:

None

subscribe_to_attribute(attribute_id, on_message)#

Subscribes to changes of an asset attribute using a NATS consumer.

Return type:

None

Parameters:

  • attribute_id (str) – The attribute ID to monitor.

  • on_message (AssetNATSCallback) – Callable that takes (msg_subject: str, msg_value: dict) and handles messages.

subscribe_to_conditions(on_condition)#

Subscribes to asset conditions using a NATS consumer.

Return type:

None

Parameters:

on_condition (AssetNATSCallback) – Callable that takes (msg_subject: str, msg_value: dict).

subscribe_to_events(on_event)#

Subscribes to asset events using a NATS consumer.

Return type:

None

Parameters:

on_event (AssetNATSCallback) – Callable that takes (msg_subject: str, msg_value: dict).

subscribe_to_messages(on_message)#

Subscribes to asset messages using a NATS consumer.

Return type:

None

Parameters:

on_message (AssetNATSCallback) – Callable that takes (msg_subject: str, msg_value: dict) and handles messages.

subscribe_to_samples(on_sample)#

Subscribes to asset samples using a NATS consumer.

Return type:

None

Parameters:

on_sample (AssetNATSCallback) – Callable that takes (msg_subject: str, msg_value: dict).

property type: Literal['Samples', 'Condition', 'Events', 'Method', 'OpenFactory', 'UNAVAILABLE']#

Retrieves the type of the asset from ksqlDB.

Executes a SQL query to fetch the asset type. If the query returns no result, the method defaults to UNAVAILABLE.

Returns:

Literal[‘Samples’, ‘Condition’, ‘Events’, ‘Method’, ‘OpenFactory’, ‘UNAVAILABLE’] – The asset type as stored in the assets_type table, or UNAVAILABLE if not found.

wait_until(attribute_id, value, timeout=30, use_ksqlDB=False)#

Waits until the asset attribute has a specific value or times out.

Monitors either the NATS cluster or ksqlDB to check if the attribute value matches the expected value. Returns True if the value is found within the given timeout, False otherwise.

Return type:

bool

Parameters:

  • attribute_id (str) – The attribute ID of the asset to monitor.

  • value (Any) – The value to wait for the attribute to match.

  • timeout (int) – The maximum time to wait, in seconds. Default is 30 seconds.

  • use_ksqlDB (bool) – If True, uses ksqlDB instead of NATS to check the attribute value. Default is False.

Returns:

bool – True if the attribute value matches the expected value within the timeout, False otherwise.